420 Words. Plan about 1 minute(s) to read this.
A few days of dealing with life, and back at the CCIE study. I built a 2621XM and threw it on the network here for something to do. It needed new IOS, put 12.4.12 Advanced Security on it. Not sure it’s the most appropriate feature set, but it’ll do for now. I wanted a router I can just hack on to see commands and so forth, get a better feel than merely what it says in the book. I have 2 other routers and some more 2950 switches I can use to cluster a little lab together. I also need to take one of my myriad spare PC’s and make a console server, I think. Dunno. Kind of depends on how building the lab at work goes, since that’s where I think I can build my monster. We shall see…maybe I just bring more gear home from work if they let me. What the heck, it’s just an electric bill…
Anyway…all this rambling is taking way from study of RIP v2. OECG Chapter 8 covers this dusty topic, a protocol none of us really ever run anymore, but probably all touched it at one time or another in the past.
A summary of RIPv2 features:
- UDP port 520.
- Main metric is hop count (ergo RIP isn’t the sharpest knife in the drawer if left to itself). 15 hops is as far out as RIP can grasp. 16 hops is considered to be an infinite number of hops away.
- There is no hello interval. RIP stays in touch by receiving full routing updates periodically. There is no formal neighbor relationship.
- When RIP v2 updates, it does it with a 220.127.116.11 multicast. RIP v1 used 255.255.255.255.
- Update interval is every 30 seconds.
- No partial updates. Full updates all the time, every time. For on-demand circuits, RFC 2091 allows RIP to send a full update the first time, but not say anything else until a change happens.
- When routes change, this will trigger an update.
- Supports up to 6 equal-cost routes in the routing table, with a default of 4.
- You can authenticate both via MD5 or plaintext.
- RIP v2 is classless, as it includes the subnet mask in route advertisements. Ergo, VLSM is supported.
- Route tagging is supported (more on that later).
- There’s a “next-hop” field so that the router can advertise routes other than itself as the next-hop.
- RIP does not compute the metric for itself. Rather, RIP accepts the metric (hop count, remember?) that’s advertised to it. When the router advertises the route it’s learned, it will add 1 to the metric.
Ethan Banks writes & podcasts about IT, new media, and personal tech.
about | subscribe | @ecbanks